The 5 ssp_cat_1 and the 9 ssp_cat_2 colour schemes are not consistent with each other:
I understand and agree with the ssp_cat_1 scheme: it has been used by many of the IIASA/IAM publications since circa 2017 (e.g. https://www.sciencedirect.com/science/article/pii/S0959378016300681), and many in the literature will be familiar with them, in a way that the AR5 RCPs have become familiar to many.
The ssp_cat_2 colour scheme should follow these for visual continuity: with two different shades of green for SSP1-1.9 and SSP1-2.6, two orange/yellow for SSP4-3.4 and SSP4-6.0, and two maroon/purple/pink for SSP5-8.5 and SSP5-3.4OS. I have heard the argument that the ssp_cat_2 scenarios are coloured as they are to follow approximately low to high radiative forcing = cool to warm pattern, but I argue that SSP4 is a rather "cautionary" tale in socio-economic terms and should be coloured as such (more of WG3 remit than WG1, but we should be consistent), even though SSP4-3.4 has lower forcing and expected to be cooler than SSP2-4.5.
The 5 ssp_cat_1 and the 9 ssp_cat_2 colour schemes are not consistent with each other:
I understand and agree with the ssp_cat_1 scheme: it has been used by many of the IIASA/IAM publications since circa 2017 (e.g. https://www.sciencedirect.com/science/article/pii/S0959378016300681), and many in the literature will be familiar with them, in a way that the AR5 RCPs have become familiar to many.
The ssp_cat_2 colour scheme should follow these for visual continuity: with two different shades of green for SSP1-1.9 and SSP1-2.6, two orange/yellow for SSP4-3.4 and SSP4-6.0, and two maroon/purple/pink for SSP5-8.5 and SSP5-3.4OS. I have heard the argument that the ssp_cat_2 scenarios are coloured as they are to follow approximately low to high radiative forcing = cool to warm pattern, but I argue that SSP4 is a rather "cautionary" tale in socio-economic terms and should be coloured as such (more of WG3 remit than WG1, but we should be consistent), even though SSP4-3.4 has lower forcing and expected to be cooler than SSP2-4.5.